Why is my Mindtex-generated normalmap rendering weirdly in Cycles?
Use a normal map node between your image texture node and your normal input. As you already have, the image texture should be set to Non Color Data.



From the manual:


  The Normal Map node generates a perturbed normal from an RGB normal map image. This is usually chained with an Image Texture node in the color input, to specify the normal map image. For tangent space normal maps, the UV coordinates for the image must match, and the image texture should be set to Non-Color mode to give correct results.